1. Field of the Invention
The present invention relates to an image measuring method for using images from a plurality of viewpoints to simply and accurately extract image-pickup parameters in photographing an object, e.g., the pose, position, base length, vergence angle, focal length, and aberration information of a camera, and an image processing apparatus for measuring the three-dimensional shape of an object on the basis of image-pickup parameters to display the three-dimensional shape.
2. Description of the Related Art
A conventional method of measuring three-dimensional shape data of an object from an image, using a stereo measuring method by a binocular camera is known, as described in the xe2x80x9cImage Processing Handbookxe2x80x9d edited by Onoue, et al, Shokodo, 1987. A method of extracting relative positions (parallel movement amount and rotational movement amount) of all shape data of the object and a method of integrating the relative positions, which methods are based on the above stereo measuring method, are disclosed in Japanese Unexamined Patent Publication Nos. 5-303629 and 6-208610, the Institute of Electronics Information and Communication Engineers paper D-II (Vol. J75-D-II, pp. 737-748, 1992).
According to these methods, the relative positions of a plurality of partial shape data are calculated by using only the image of an object so as to calculate a whole three-dimensional shape without directly measuring the relative positions of the object and a camera by sequentially connecting the partial shape data to the camera. A method in which the camera has a pose detection sensor arranged thereon to use pose data and image data is disclosed in Japanese Unexamined Patent Publication No. 6-241731. In addition, a method of calibrating the three-dimensional position and pose of an image-pickup means by image measurement is disclosed in Japanese Unexamined Patent Publication No. 6-259536.
However, of the above prior art, the method disclosed in Japanese Unexamined Patent Publication Nos. 5-303629 and 6-208610, the Institute of Electronics Information and Communication Engineers paper D-II (Vol. J75-D-II, pp. 737-748, 1992) cannot always accurately calculate the relative positions between the camera position and the partial shapes without measuring the shape of the object and a pattern on the object surface, and the following problems arise. That is, errors occurring in integrating shape data are accumulated, and a calculation amount becomes large.
According to the method disclosed in Japanese Unexamined Patent Publication No. 6-241731, since parameters other than the pose of the camera are obtained on the basis of the image data, the same problems as described above arise. In any example, the base length, vergence angle, focal length, distortion, and aberration information of the camera must be accurately calibrated in advance. Therefore, when an object is photographed, the position and pose of the camera, which parameters are inherent in the camera cannot be adjusted.
In Japanese Unexamined Patent Publication No. 6-259536, the following problems arises. That is, accuracy and calculation stability are poor because an image at one viewpoint positionis used, or the same problems as described in the prior art arise when the method is applied to three-dimensional shape measurement because the focal length of the image-pickup means is not extracted.
The present invention has been made to solve the above problems of the prior art, and has as its object to provide an image measuring method and apparatus capable of easily extracting an image-pickup parameter at a high accuracy by inputting an object image, and measuring the image.
Therefore, according to a preferred embodiment of the present invention, there is disclosed an image processing method and apparatus characterized in that, on the basis of images from a plurality of viewpoint positions including a known pattern and an object, image-pickup parameters of the image are extracted.
According to another preferred embodiment of the present invention, thereis disclosed an image measuring method and apparatus characterized inthat a pattern having features whose positional relationship is known is defined as a first object, and a predetermined object is defined as a second object, and image-pickup parameters are extracted on the basis of images from a plurality of viewpoint positions of the two objects.
It is another object of the present invention to measure a three-dimensional shape at a high accuracy with a simple arrangement.
In order to achieve the above objects, according to still another preferred embodiment of the present invention, there is disclosed an image measuring method and apparatus characterized by input means for inputting unknown object images obtained by viewing, at a plurality of viewpoint positions, a first object having features whose positional relationship is known and a second object having a three-dimensional shape which is at least partially unknown; image-pickup parameter extracting means for extracting image-pickup parameters corresponding to the object images; three-dimensional shape information extracting means for extracting three-dimensional shape information of the second object; recording means for recording the three-dimensional shape information; and image display means for displaying an image.
According to still another preferred embodiment of the present invention, there is disclosed an image measuring method and apparatus characterized by image inputting means for inputting unknown object images obtained by viewing, at a plurality of viewpoint positions, a first object having features whose positional relationship is known and a predetermined second object; means for extracting image-pickup parameters corresponding to the object images; image recording means for recording the object images; image-pickup parameter recording means for recording parameters corresponding to the object images; and image. display means for displaying an image.
The other objects and characteristic features of the present invention are understood with reference to the following specification and drawings.